[binarymax]

The thing that I like about Duckling is that it is a rules based system, which can easily be interrogated. Model based text extraction is much harder to fix when there is a bug. I use Duckling as a service in value extraction from queries and content alongside a model based system for NER (such as spaCy). Using both together makes for more accurate enrichment in general (by cross referencing between the two for values, and adding exception rules)

[ar7hur]

It's exactly how we used it internally for wit.ai

(Very small correction: Duckling is rule-based but uses a super simple Naive Bayes classifier to prioritize between the many potential parses produced by the rules -- we see it as a hybrid approach)